/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.iteration.datacache.nonkeyed;

import org.apache.flink.annotation.Internal;

import java.io.IOException;
import java.util.Optional;

/** Writer for the data to be cached to a segment. */
@Internal
interface SegmentWriter<T> {
    /**
     * Adds a record to the writer.
     *
     * @return true if the record is successfully added, false if the size of the segment has
     *     reached {@link DataCacheWriter#MAX_SEGMENT_SIZE} and cannot add current record.
     */
    boolean addRecord(T record) throws IOException;

    /**
     * Finishes the writer and returns a segment if any record has ever been added through {@link
     * #addRecord(Object)}.
     */
    Optional<Segment> finish() throws IOException;
}
